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HelpTest Code URAU Urea, 24 Hour, Urine
Reporting Name
Urea, 24 HR, UUseful For
Assessment of protein intake and/or nitrogen balance
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
UrineNecessary Information
1. 24-Hour volume (in milliliters) is required.
2. For any timed collection the volume and length of collection is required.
Specimen Required
Supplies: Sarstedt 5 mL Aliquot Tube (T914)
Container/Tube: Plastic, urine tube
Specimen Volume: 4 mL
Collection Instructions:
1. Collect urine for 24 hours.
2. Mix well before taking aliquot.
Additional Information: See Urine Preservatives-Collection and Transportation for 24-Hour Urine Specimens for multiple collections.
Specimen Minimum Volume
1 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Urine | Refrigerated (preferred) | 14 days | |
| Frozen | 30 days | ||
| Ambient | 7 days |
Special Instructions
Reference Values
≥18 years: 7-42 g/24 hours
Reference values have not been established for patients who are less than 18 years of age.
Test Classification
This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.CPT Code Information
84540
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| URAU | Urea, 24 HR, U | 48999-7 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| UREA | Urea, 24 HR, U | 48999-7 |
| TM33 | Collection Duration | 13362-9 |
| VL31 | Urine Volume | 3167-4 |
| URECN | Urea Concentration | 63481-6 |
Clinical Information
Urea is a low molecular weight substance (60 Da) that is freely filtered by glomeruli, and the majority is excreted into the urine, although variable amounts are reabsorbed along the nephron. It is the major end product of protein metabolism in humans and other mammals. Approximately 50% of urinary solute excretion and 90% to 95% of total nitrogen excretion is composed of urea under normal conditions. Factors that tend to increase urea excretion include increases in glomerular filtration rate, increased dietary protein intake, protein catabolic conditions, and water diuretic states. Factors that reduce urea excretion include low protein intake and conditions that result in low urine output (eg, dehydration).
Interpretation
Because multiple factors (glomerular filtration rate, dietary protein intake, protein catabolic rate, hydration state, etc.) can independently affect the urinary excretion of urea, all of these factors must be taken into account when interpreting the results.
Reject Due To
| All specimens will be evaluated at Mayo Clinic Laboratories for test suitability. |
Cautions
No significant cautionary statements
Method Name
Kinetic Ultraviolet Assay
Forms
If not ordering electronically, complete, print, and send a Renal Diagnostics Test Request (T830) with the specimen.
Day(s) Performed
Monday through Sunday